Research And Application Of Load-bearing Characteristics Of Strong And Tough Cemented Filling Materials

Cemented filling materials for mines are widely used in projects such as coal resource replacement mining and roadway retention along goafs.The effectiveness of the cemented filling material mainly depends on its load-bearing stability.From the perspective of improving the comprehensive load-bearing stability of the cemented filling material,taking into account the green concept of secondary utilization of mine waste,this paper systematically studies the physical and mechanical properties of the cemented filling material on the basis of the innovative material ratio,and satisfies the flow The interval ratio of the strong and tough cemented filling materials required by the performance requirements reveals that the different properties of the materials in this paper are affected by variable factors such as the ratio of fly ash to the fine aggregate mass ratio and the volume ratio of steel fiber in the ratio,and it is clear that the steel fiber damages and destroys the material.Based on the influence of the characteristics,the damage and destruction equation of the cemented filling material in the ratio range of this paper is established,and the interval filling system is designed with the background of the coal resource recovery of a certain mine "three under".The research results can provide reference and parameter support for the research on the ratio of cemented filling materials and the application of downhole filling engineering.The main research results are as follows:(1)Through innovative material ratio,a strong and tough cemented filling material that meets fluidity requirements is obtained.The variable factors of the ratio make the cemented filling material change from low strength and high brittleness to high strength and high toughness.Among them,the variable factor of fly ash mainly enhances the cemented filling material,and the variable factor of steel fiber mainly increases the cemented filling material.The effect of ductility(toughening),the overall improvement of the material's comprehensive load-bearing performance is the increase in strength,increased ductility,and better integrity after failure.(2)The influence law of variable factors on the comprehensive properties of cemented filling materials is obtained.Among them,the influence of fly ash on the material strength characteristics is divided into two different stages in the ratio range with 40% as the turning point.According to the change law of the material peak strength with the volume rate of steel fiber,it is proposed that the material strength characteristics have Universally adaptable "bonding-connection dual-cause two-way effect".(3)It is clarified that the damage evolution characteristics and the final failure form characteristics of cemented filling materials under continuous uniaxial compression are affected by steel fibers.The damage evolution and failure modes of the cemented filling materials when steel fibers are mixed and those without steel fibers are shown separately Obvious ductility characteristics and weak ductility or brittleness characteristics.(4)Two damage and failure evaluation or prediction equations based on the peak strength of the material are established,which can realize the estimation and prediction of the peak failure strength value under any value of the variable factor in the ratio of the cemented filling material in this paper.(5)Based on the research results,combined with the actual application background conditions of a mine in Inner Mongolia,the A5 ratio cemented filling material is selected for the replacement mining of the first working face of the 3-1coal seam,and the stability of the overburden and the stability of the cement are fully considered and the theoretical analysis is passed.,Numerical calculation and other methods have determined the spacing and layout parameters of cemented backfills,and designed a backing and recovery system.